1. Field of the Invention
The present invention relates to a character input apparatus, a character input assist method, and a character input assist program which can be suitably used when inputting characters on a portable terminal, such as a cellular phone terminal, which can be provided with only a limited number of keys, for example.
2. Description of the Related Art
Portable terminals, such as cellular phone terminals, generally cannot have a large space for operation devices for a user interface. In recent years, it is essential for even the portable terminals, as well as common personal computers, to have a character input and editing function, a function of accessing the Internet to display a web page, and the like.
In the case of the cellular phone terminals, which are examples of the portable terminals, a so-called numeric keypad (which is composed of numeric keys for “0” to “9”) and symbol keys for “#” and “*” are used as operation devices for character input and editing, and an arrow key (i.e., a so-called cross key) used to specify directions, such as “→” (Right), “←” (Left), “↓” (Down) and “↑” (Up), or the like is used as an operation device for cursor movement and screen scroll. The ten keys that constitute the numeric keypad and the two symbol keys are sometimes referred to collectively as “twelve keys.”
Many recent cellular phone terminals have a so-called predictive conversion function as a function for assisting a user in the character input. The predictive conversion function can have a variety of modes. Generally speaking, the predictive conversion function predicts (infers) a character, word, or the like that the user is now attempting to input, based on a character, word, clause, or the like that is now being inputted or which has already been inputted; displays, on a screen, a list of candidate characters, candidate words, candidate clauses, or the like (hereinafter referred to collectively as “predicted candidates”) obtained as a result of the prediction; and, when the user has selected and determined his or her desired one of the predicted candidates in the list of the predicted candidates, determines the selected predicted candidate as an input character, an input word, or an input clause.
For example, Japanese Patent Laid-open No. 2003-216606 (Japanese Patent Laid-open No. 2003-216604 (FIG. 1)) discloses an input character information conversion apparatus and a monitor apparatus. In this related-art technique, a plurality of predicted candidates based on character information inputted by a user using keys or the like are displayed on a screen of the monitor apparatus to present the predicted candidates to the user, and, when the user has selected his or her desired predicted candidate from among the displayed predicted candidates, the selected predicted candidate is entered (so-called predictive conversion).
According to this related-art technique, the plurality of predicted candidates based on input character information are presented to the user as predicted candidates selectable by the user, and the user is able to input a character(s) simply by selecting his or her desired predicted candidate from among the plurality of predicted candidates presented.